1. Technical Field
The present invention relates to a tablet feeder.
2. Description of Related Art
As a tablet feeder, there has conventionally been one that is composed of a case support base on which a motor is provided and a tablet housing case attachable to and detachable from the case support base. This type of tablet feeder is structured such that drive of the motor rotates a rotor disposed in the tablet housing case via a plurality of gears so as to discharge tablets held in the pockets of the rotor from a discharge section.
When a tablet is supplied to a tablet housing case, the tablet housing case should be temporarily detached from the case support base. In this case, the rotor comes into a rotatable state, and so the tablets housed therein might fall down. Accordingly, in order to prevent automatic rotation of the rotor and discharge of the tablet, there has been proposed a structure for preventing rotation of the rotor by pressing a plate spring and the like to the gear that is interlocked with the rotor (see Japanese Patent Gazette No. 3040396, Japanese Patent Laid-Open Publication No. 10-314277, and Japanese Patent Laid-Open Publication No. 2000-43801 for reference).
Further, when the tablet housing case is detached from the case support base, tooth bearing of the gear on the case support base side and the tablet housing case side is changed, which sometimes causes slight rotation of the rotor. In this case, depending on the stop position of the rotor, tablets held in the pockets may be discharged from the discharge section.
Accordingly, in order to prevent rotation of the rotor when the tablet housing case is detached from the case support base, there has been proposed a structure having an elastic engagement member which engages with the gear that is interlocked with the rotor to prevent the rotor from rotating when the tablet housing case is detached from the case support base (Japanese Patent Laid-Open Publication No. 9-323702).
However, the above-described conventional structures require a plate spring and an elastic engagement member, which complicates the structure and causes increased costs. Moreover, in the state that the tablet housing case is attached to the case support base, force always acts upon the plate spring and the elastic engagement member, so that the long-term use thereof may disable the plate spring and the elastic engagement member from sufficiently fulfilling the role of preventing rotation of the gear. Furthermore, when the tablet housing case is detached from the case support base, it is not possible to avoid the rotation of the gear before the force from the plate spring and the elastic engagement member acts thereon.